There are many factor that may influence a population's size. Food, habitat, mating, environmental characteristics and human caused selective pressures such as hunting and pollution can effect a population. The most important and influential of these factors currently is habitat destruction. Due to the growing number of people on our planet, ecosystems are being destroyed and replaced with residential and urban ares. Pollution also plays a role because improper disposal and treatment of waste. Air pollution can lead to inhabitable conditions within a region, such as acid rain, which makes lakes and streams "die" as a result of an unbalanced pH level. Hunting can also create an unhealthy dive in a population when it is unregulated. This can be seen by the Dodo's extinction to due to over hunting and exploitation. Natural causes such as food sources and ability to adapt leads to a species increase or decrease. If the raw needs or an organism are supplied by its environment, it will flourish. Inversely, if the needs of a species are not met by its environment, it will not be able to have success and ultimately will not reproduce as much because the environment cannot support as many organisms, thus leading to a decrease.
There are many factor that may influence a population's size. Food, habitat, mating, environmental characteristics and human caused selective pressures such as hunting and pollution can effect a population. The most important and influential of these factors currently is habitat destruction. Due to the growing number of people on our planet, ecosystems are being destroyed and replaced with residential and urban ares. Pollution also plays a role because improper disposal and treatment of waste. Air pollution can lead to inhabitable conditions within a region, such as acid rain, which makes lakes and streams "die" as a result of an unbalanced pH level. Hunting can also create an unhealthy dive in a population when it is unregulated. This can be seen by the Dodo's extinction to due to over hunting and exploitation. Natural causes such as food sources and ability to adapt leads to a species increase or decrease. If the raw needs or an organism are supplied by its environment, it will flourish. Inversely, if the needs of a species are not met by its environment, it will not be able to have success and ultimately will not reproduce as much because the environment cannot support as many organisms, thus leading to a decrease.